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Stored energy

    Alot of people have amazing instructables on how to gather energy  be it solar, wind or hydro electric but not alot on how to store it. So I guess what i really need is some storage instructables cuz Im at a total loss. Please help. 

Topic by hackencoff    |  last reply


Carbon Fibre Flywheel (for energy storage)

I'd like to build a flywheel but I'm not sure what I need to know before i start, Is it difficult to do? Is it possible to accomplish with off the shelf parts? Any help at all would be appreciated greatly.

Topic by nuncoop    |  last reply


Hydro Power generation from water service . Question?

Has  anyone  ever  tried  or thought   about some how  rigging  a  hydro  generator  maybe   some type  of   enclosed   padel   system  onto  the    supply water  service   from the street to the  house?  I cannot help  but think   their should besomeway to harness    the  energy of   public  water system .  As many loads  of  cloths  as i  see  my wife  washing  and  the dishwasher  seems  to   be  alot fo wasted  energy. Just  curious . Andy

Question by andy1917    |  last reply


Energy saving ideas???

I am on a fixed income and need homemade project ideas to cut my hydro bills down that have doubled in the last 3 years. Any low cost project plans would be helpful to me and my family. Thanks!

Question    |  last reply


Idea to Store Solar, or Wind Energy in Tanks in Central, South American, Africa

 I go to Togo, West Africa, and they already use, or need the black water tanks. they can have the water pumped using solar, windmills, or rope pumps, then allow it to fall, and light their houses with LED lights, and charge their cell phones. So what do you think, anyone have experience using these cheap hydro generators? Do they work? Do they last? Is there enough water pressure? Thanks, Andy Lee Graham https://www.hobotraveler.com/blogger.html

Topic by hobotraveler    |  last reply


Solar storage help

Hello! I'm new to the forums, but I've read many instructables. I'm looking to create a solar-charging messenger bag. I decided on a powerfilm flexible solar cell that is 7.2v 200mA. Amazon has them for slightly above $50. I originally wanted to use a xtreme mac Incharge portable to store the power,(PLEASE CORRECT ME IF I AM WRONG) but I think that may take too much to convert it from 120v in to 7.2v in. The benefit of this item is that it has two 1w usb output charging terminals. That means faster charging.  The second idea is to send the solar energy to four AA Energizer rechargeable (1.2v 2500mAh) NiMH batteries. The benefit of using AA batteries is they can be used for other things and that they can be easily replaced after running through charging cycles(I don't know the life cycle of rechargeable batteries anymore). Any assistance offered would be greatly appreciated. I have the bag, will be ordering the solar cell later this week, found the incharge portable at a thrift store, and always have plenty of batteries and wires. Thanks!

Topic by chokingjaik  


Hydrogen for renewable energy storage- total system efficiency?

This is a question that has been bugging me for some time, especially since the questions about methanol synthesis revived my interest in energy storage. Say I have a wind turbine or solar panel or whatever, that produces 1000 Wh per day.  If I use that electricity to electrolyse water, store the generated hydrogen at roughly atmospheric pressure in an upside-down water butt or a big gas-tight bag in my shed (don't worry, I'm not going to actually do this) and then feed it into a generator converted to run on H2, what percentage of that initial energy input would I get back out?  20%?  5%? 1%? The follow-up questions to this are a) How does that compare against a battery bank? What about a similar DIY-style pumped water storage system? b) What one component of the system should be improved to raise the overall system efficiency? Electrolyser, storage, generator? c) Are there any other DIY-friendly methods for storing intermittently generated electricity that I'm not thinking of? And, I suppose, d) Does doing this and providing 5-10x your overall power requirements in wind turbines work out cheaper than spending thousands on batteries?

Topic by PKM    |  last reply


can i build a dual turbine which is powered by steam which is condensed and released like a water wheel. would it work?

If I build a steam turbine powered by burning waste using a pelton turbine then the steam will travel upwards. if I condense and store it, then release it past another pelton turbine to restart the cycle then will it be equally efficient. assuming the fuel source is free can this be practical in terms of electricity generation?

Question by mrgre99    |  last reply


Anyone achive solar power overnight?

Here is how to do it: Use a standard 55 gallon steel drum and stick one of these on it. http://ieverred.en.made-in-china.com/product/tqZQNGTCJARz/China-Thermoelectric-Power-Generator-TEC1-031100-.html Provide water cooling for the TEG: http://www.customthermoelectric.com/Water_blocks.html If your water is 20 Celcius, you should pump 36 Litres/hour to keep max power output. Also hook up piping for hot oil for heating Now wrap it with 400 mm of rockwhool insulation. Fill it with molten salt and heat it to 250 Celcius. Tadaa: 24 W of power output, round the clock. (minus the power for the cooling pump, maybe 1-2 W) I calculate that the temperature will drop from 250 to 225 Celcius in 16 hours. To get the temperature back up in 8 hours you need to heat it with 2400 W. You can do this easily with a solar trough system of about 3 m2. A trough is good because you only need to align every few days. Budget Oildrum 50$ ? Salt 370 kg  = 150$? TEG 80$ Cooler 80$ Pump 15$ Piping 100$? Trough (plastic sheet and mylar) 100$? high temperature oil pump 500$ ? About 1000@ total. Does seem like a lot for a little. Anyone have a better idea?

Question by eripe    |  last reply


The future of "mobile" energy...

Right now our current standard is still to use LI-Ion batteries when it comes to rechargable and power demanding devices.We all want more power for our phones, laptops or battery powered tools on the job.And we also want to be able to charge our batteries faster and faster.Back in the old days a D-Cell like lead acid battery in a flashlight was good for about 3 hours until it started to dim a bit.With up to 4 batteries inside they were not just heavy but also quite hazardous.Chargin was usually done over night and you just hoped they were not blowing up while charging.I spare you the other types that came after and that we still use as they all have their good and their bad sides.If we trust our marketing experts than quite soon we will only have electric cars on our roads and battery the size of a suitcase shall be able to run your car for hundreds of miles.The ideas of graphite based batteries or those using crystals and their forming reactions are all great and promising.Some will certainly make it to the consumer in a few years.The one thing that we are never told though is where all the energy to charge those batteries is supposed to come from.Replacing the combustion engine with electric motors is one thing but if no fossil fuel is used....Energy does not come out of thin air!Right now a lot of countries already struggle to provide a reliable power supply grid and distribution network.If you ever enjoyed a scorching hot day during a blackout caused by everyone using too much electricity you know what I mean...The population is growing as fast as the energy demand for our industries.Solar and wind are well and good but without proper storage solutions of not real use because no one can really predict how much they can produce.You know, weather and such things...If we trust our so called experts than all will come together really nice.By the time we have really powerful batteries we will have enough alternative energy supply chains up and running to keep them charged.I have a few issues with this entire concept, so let's see what other people have to about this:Imagine you have a nice and big cabin somewhere really remote and beautiful - but with no electricity for miles.Obvious solution for the modern hunter or nature lover is to invest into free energy.Free because that is how your solar, battery and inverter system would be advertised.You buy the stuff and after that all the electricity comes for free - the things pays for itself!Reality is a bit off though as you need to maintain and replace the costly batteries over time and such things.All this however totally changes for a residential home.Getting a huge solar system on your roof is no problem.Getting off the grid next to impossible.You see, once (or even before) you sign up for an electricity contract it is defined that your home is in a residential area.This brings certain limitations like the requirement to connect ot gas (if available), water, sewage and electricity.Only way to enjoy your "free" energy is by getting a good deal with your supplier.Some countries do it differently but around here it goes like this:Whatever you use still comes right off the grid.That is because your solar system really struggles to cope with load changes and providing surplus back to the grid.And since your meter is not capable ofworking properly with it either...To make it "fair" it is metered how much you use and how much you supply.Most companies here even do this on at least an hourly base - just to fair...For your bill the amounts are then adjusted.What you supplied is taken off.Sadly in most cases going negativ is not an option - if you provide more than what you use only your supplier is laughing.To make things worse what you supply is valued far lower than what you get from the grid.Often the difference is above 20%.Control....Around here quite a few people basically covered house, shed, carport and all with solar panels.This was while we had a great subsidy from the government to go solar...After now over three years most of these people still struggle to get anywhere near even for their investment.Without the grants the timeframe to break even was estimated to be around 12 years - which is about the time for when you need to replace the lot anyway and start over.Some do get nice savings on their bills though but families with kids not so much...If you have little to no chance to get your investment back before you have to replace it, then it is not really that much of a good deal after all.Imagine in town with hundreds of small houses everyone would be able to get the same money back for the electricity they provide...Pay 18 cents per kWh from the grid and get 18 cents perkWh for what you supply and once you provide more than you use you get money back.The providers won't allow this to happen as it means they not just loose some money but also they would lose control.How could they justify another price hike?How could they explain the blackouts?Why should tey pay you at all... ;)If a city with enough open and unused space would decide to go solar on a huge scale and while add also add a lot wind turbines....Someone would need the electricity provided and someone need to step in for those times where demand is above supply.Here the old triangle of power goes into full swing....You see a city or town would need also need a sub station to handle the electricity and to distribute it to the town houses, shops and so on.Funny thing is that only a "provider" can do such things.Doing it privat is usually only possible in really remote areas, like big mining outposts that just have no other option than using generators or solar/wind.And in most areas a town or city is no longer allowed to be a provider of electricty - at least not in the drirect form.Buying in bulk is no problem, having your own supply system however is not in the books.Right now most, if not all the big wind and solar farms are owned and operated by energy providers.There is billionaires everyhwere who could build a solar and wind farm the size of Texas if they really wanted but they won't do it either...Starts with the land, goes over the usage rights and won't end with activists claiming how bad it all is.Means it won't happen and if it does then the energy providers get together and claim they guy might have money but does not have the right to provide energy unless he actuall starts a corresponding company and plays by their unwritten rules.Can we still dream about it though?The dream is kept alive like the fire of hope that is only a tiny amber.If you sign up for electricity you are asked if you would like to pay bit extra so your electricity comes from alternative sources.Why is that bad, after all it is green?The initial investment might be huge for a wind farm but after that it is more or less just providing mone out of thin air.You can look the cost up for the new windfarm build near you.Same for the electricity prices in that area.And also the expected output of the entire farm.Do the math and calculate how quickly they break even....Once they do it only profit but you still pay the extra to go green.A bit like the new road that came with a toll....After 5 years the motorists paid it off but 10 years later they are still being charged while the road is disintegrating...Now add electric cars and our constantly rising consumption to the mix...We can't provide the electricity ourselfs as we don't get fully paid for it, we can go off grid either.The atom as the source of electricity is being phased out slowly as well.Finally as some might say, considering the thausands of years we have to deal with the produced waste and what aftereffects the storage might bring.Our providers will keep their grip on us for as long as they can.No government will stop them as in return they wouldn't have electricity.A cold war if you like.We never cared how much fuel our cars use until the OPEC decide to limit supplies and drive the prices up.And you can see the riches especially in Saudi Arabia.For most of the big OPEC players it really does not matter anymore whether or not they have oil or not.They make the same or even more money by other means and more modern means now.After this initial shellshock we woke up and decided that for the shopping trip of the wife a small car with just 4 cylinders will do.Overcrowded cities and roads also pushed us more into thinking small.Again it took force to go further, this time by governments slowy "going green".Emmissions, greenhouse gasses, polution, particles and corbon monoxide...Sounded all godd in the ads but it meant we could no longer afford our old car or even got banned from entering the town center with it.But a lot people still can't afford a modern car that meets the standards.Once they finally got the money and car the laws change again and they need yet again a newer car.This created a huge export and recyling market and profits for other people though.And what differenc did it all make in reality?While we were forced to improve and lose money countries like the US refused for years to even consider reducing the pollution.Countries like China and Russia even increased their pollution to impossible levels.We all remember how Bejing was literally shut down for the Olympics so the athletes have a chance to survive the games...We know how the pollution or global warming problem is misused to make money.The governments get huge payouts in the form of taxes from those cars that can't meet the specs.The dealer smiles with the increased sales of cars.And again the government smiles too as they get taxes from this as well.We know it happened before and is still happening with everything realted to fossil fuels, global warming and pollution, so why would electricity be any different?Reactors and coal fired power plants are phased out with basically nothing to replace them.Solar and wind will provide and till then we keep what we really need to keep....There is no plan for what comes after coal and the atom.There is no alternative.Batteries need electricity.And providers will always be the middleman controlling both the price and the availability.So how does this actually work you might wonder...No matter who invents or produces a new device to provide electricity - there is a very limited market for them.A farmer can't buy a full size wind generator and place it on his land...But an electricity provider can buy thausands of them....And if you go bigger than ask yourself who would need a 10 or 100MW fusion generator?Providing electricity is only a viable option if you go big and if you can sell the excess with a profit margin.Leaves only our electricity providers as customers.If you don't have to care about the buying price because it will be put down one way or the other onto your customers than it is like a credit.Only difference is that once it is paid off you start to get money back!Imagine that for your bank account ;)And if you know what you sell can have a very generous profit margin because your buyer does not care then the solar or wind farm will be quite costly to build..."We know we are not cheap, but who else can deliver you what you need?"And like our big supermarkets there will be an agreement on what the wind generator can cost.Ressources....Be it wind, be it solar or just the modern electric motor in your car - they all require stuff that is very limited on our planet.Take Neodyminum.Without it we have no wind generator or fancy motors as we wouldn't have powerful enough magnets.Vital elements and mineral required are only available in a few spots on our erth in quantities justifying mining them.I won't make this much longer than it already is, so please look up what is really needed to keep our future solow and wind projects alive.Then go and check where we can find thes things in good quantities.Once you did you might realise why the world tolerates the abuse of human rights, freedom or just self expression in other countries ;)If only China would stop today to export and sell their rare earths and prcious minerals basically our entire production worldwide would suffer quickly.Entire industries break down quickly and prices for certain things would literally explode.The US already started to re-open long abandoned mining projects as suddenly even the most costly operations become viable again.Think about this next time you fancy a world free of cars and truck using combustion engines ;)

Topic by Downunder35m    |  last reply


How to build a clockwork robot?

Http://www.dailykos.com/stories/1632015#comment_65467648 To enter the Fukashima U2 with radiation at 1000 SVR plus can a clockwork autonomous robot gathering data with sonar be designed to go where no autonomous robot has gone before. The reason is all electronic devices would cease to function at about half that  SVR level. The clockwork mechanism would need to be designed to provide autonomous movement  so all sensors would have to be non electronic devices. Might mechanical sound, pressure, temperature or other forces be used for controls? Is it possible to provide a mechanical power storage source Compressed air energy storage (CAES) Fireless locomotive Flywheel energy storage Gravitational potential energy (device) Hydraulic accumulator Liquid nitrogen Thermal Brick storage heater Cryogenic liquid air or nitrogen Eutectic system Ice storage air conditioning Molten salt Phase Change Material Seasonal thermal energy storage Solar pond Steam accumulator Thermal energy storage (general) Chemical Biofuels Hydrated salts Hydrogen Hydrogen peroxide Power to gas Vanadium pentoxide What sort of time/energy is achievable?

Question by Rowland Whittet    |  last reply


can someone look at this (simple) electricicity generation proposal and give me some tips. (with pictures)?

I want to use the wallpaper stripper for the prototype and if it works replace it with a combined heat, cooking, hot water system. Will adding the hydro have an advantage. the main reasoning behind this is using steam but not in a closed system as I dont have the engineering skills to mess about with high pressure steam. Any input is really appriciated. i have wasted enough time making things that will never be effective before finding instructables.

Question by mrgre99    |  last reply


Can I use a bunch of AA Batteries setup in cells in place of a deep cycle battery for green power storage? Answered

Hello, I have been looking more and more into solar and wind power generation as well as ways to store the power. I am still in the planning stages and have not yet tested anything. What I usually see in almost every green power storage guide is to use deep cycle batteries mostly of the types designed for solar, golf carts, etc. That would work fine but they are always rather expensive atleast any I have found online (if you know a cheaper source I would love to hear about it). So my question is this could I just buy a bulk quantity of AA NiMH (the new ones without memory) or AA Lithium ion batteries and set them up in series to make cells of 8x AA per cell for 12v total then connect all cells in parallel for my battery bank? I am not sure if this would actually be more expensive as it is just an idea I had and have been unable to find someone that tried it (perhaps I am searching for the wrong thing). It seems to me this could be more effective as I could replace one battery in the cell when it goes out and be able to constantly repair the cells in that manner. Has anyone tried this and does it work? Would it require a special charge controller unlike the usual ones sold for solar? If anyone knows of any guides that show this please share them as I would love to do more research on this before I make a decision. I think I saw once on some show that the electric car they showed was setup in this way. Anyway thank you for your assistance it is greatly appreciated!

Question by TiamatStudios    |  last reply


I need help with my digester project ? Answered

Hello i   have   attached  a  drawing  of  a project  i   am   thinking about  , but   like ususla have some  questions i  need  help with. 1.  you  see on the drawing   i  have  included   a   storage tank.  Do you think  it will work    laid out like this? 2. How  can i    compress the  methane   enough to runa    smal  generator? 3.What would  be   the size  of  teh    safety  gas  valve   i should  purchase. I have no idea of  how   much pressure  a  smll  8 to 12 hp  generator takes to   run . Any help anyone  can  give  woudl be  greatly appreciated. thanks, andy

Question by andy1917    |  last reply


Has a hobbiest ever made a compulsator?

Compulsator is a method of energy storage, give high pulse currents.

Question by rp181    |  last reply


What the Candidates Say About Energy

What the Candidates Say About Energyhttp://www.energycentral.com/centers/news/daily/article.cfm?aid=9641919RepublicansRUDY GIULIANI: Says "every potential solution" must be pursued, including nuclear power, increased energy exploration and more aggressive investment in alternative energy sources. Says energy independence can be achieved through a strategy that emphasizes diversification, innovation and conservation.MIKE HUCKABEE: Wants to lessen U.S. dependence on foreign oil by pursuing "all avenues" of alternative energy: nuclear, wind, solar, hydrogen, clean coal, biodiesel and biomass.JOHN MCCAIN: Wants to limit carbon dioxide emissions "by harnessing market forces" that will bring advanced technologies, such as nuclear energy, to the market faster. Seeks to reduce dependence on foreign supplies of energy. Wants the U.S. to lead in a way that ensures all nations "do their rightful share" on the environment. As you may know,McCain was AWOL in December on the key Senate vote to secure an 8-yearSolar Investment Tax Credit extension -- and he could have been the hero by casting the 60thvote (it failed 59 to 40 with only McCain being AWOL).MITT ROMNEY: Wants to accelerate construction of nuclear power plants as part of a "robust, cleaner and reliable energy mix." Seeks energy independence not by halting all oil imports but by "making sure that our nation's future will always be in our hands."DemocratsHILLARY CLINTON: Says she's "agnostic" about building nuclear power plants. Prefers renewable energy and conservation because of concerns about nuclear power's cost, safety and waste disposal. Wants to spend $150 billion over the next 10 years to cut oil imports by two-thirds from 2030 projected levels, with some money going toward alternative energy.JOHN EDWARDS: Opposes nuclear power because of cost and safety concerns. Favors creating a $13 billion-a-year fund to finance research and development of energy technologies; wants to reduce oil imports by nearly a third of the oil projected to be used in 2025.BARACK OBAMA: Says the U.S. can't meet its climate goals if it removes nuclear power as an option but says such issues as security of nuclear fuel, waste and waste storage need to be addressed first. Wants to spend $150 billion over the next 10 years to develop new energy sources. Seeks to reduce"oil consumption overall by at least 35 percent by 2030."

Topic by ewilhelm    |  last reply


A central non-electric grid electricity storage system for solar and wind energy with future expandibility

I have been thinking and reading about building a system so that I could surf using a laptop, charge lights, charge mp3 players, mobile phones, rechargeable batteries so that if possible they would not need electricity from the grid, rather that would be optional when there would not be enough power that was found otherwise. I had first thought to work this out in a group as a kind of project, as there are others but I don't really know that many people with those skills. The idea is that you start very basic, with say one solarcell and the electronics. The electronics should allow plug to when you wnat to have the money you can add another, in serie or parallels so they give more power. This can then be plugged in to a system that stores that electricity in batteries. The system should also be so that it allows to connect for example one or more small selfbuild wind turbines, like the ones found here, so that in the best case you get electricity from both, or one of both but with the possible option to get electricity from the grid so that if necessary you can charge something from there. That would mean it would include an electricity meter, and maybe the possibillity to add that self powering powerplant as well.So basically you have two projects. Or maybe three. The casing to add small solarcells in, and then be able to add several casing together. The electronics to put them in serie and then a central electronic system, which allows to connect solar casings, self build windmills, batteries, the self powering power plant, possibly the possibility to add it do the grid, and last but not least the possibbility to charge things. That could be a seperate part of electonics. As one of the things I had been thinking about is to allow to connect fuel cells to it. I prefer us in what already exist, so I would suggest using the following instructabels projects or learning from them:a Savonius Wind Turbine,Ted Baer's Bicycle Wheel Windmill, savonius windmill alternator,introPringles Wind Turbine,DIY 1000 watt wind turbine,A remote controlled power RGB LED mood light,Power LED's - simplest light with constant-current circuit,Circuits for using High Power LED's,personal powerPlant, ... others may follow laterLike for example the Charge Any USB Device by Riding Your Bike but then connected to the portable usb batteries, so they could be also connected to the central charge unit. The connectors could be usb connectors. I saw some time back a connector which had a 4 port usb block attached to it, but other connector types would be usable as well. In adition, it should be able to switch on automitcally when the sun goes down, but allow a control a button or remote control to trun them manually off, so that no needless electricity is wasted. I know this is a lott at once, but its more my kind of thing to work on more complete/complex systems. The lights that would be used with this would be led lights, powered a la sunjar, using the same technique. So that them turning off and on, is mostly controlled by the sun going up and down. My idea was that with such a system, I could add piece by piece, and still have light, and electricity indepency from the grid, and I would know the cost, so that once I would have bought the pieces it would generate electricty whitout to much further cost.Solarcells would typically provide 8V or 12 V, this could be smaller ones, the casing would be is supose made of plexiglas, with pieces that standup to keep them appart, and holes for the cables, and a backside, that stays dry as well. This is what is on the drawing: the solarcells feed into the sersol which puts them in not parallel and then transport the current to the cen1 which directs it to the batteries to store it. The same for the windmills. But they go to the windmills, which puts there current in not parallel. The powerreg, regulates the power of the personal power plant, it can discharge, but also just regulate. There is connector to the grid, so if there is no electricity or not enough electricity it can be taken from the grid. There is the possibillity of a remote, which would work in connection with the cen1. The batteries might need extra electronics to see which one is full and to divert the current to another battery, and to get current back to the powersockets which could be regular oens, but also preferably usb ones. The other two connections could be for for example fuel cells, or something else. The control solar cells is simply to turn the connected sunjars which may still each have there own solarcell, on or off by the rising or going down of the sunn. The remote, is to turn them off manually.The casing should be sturdy but not to expensive, it may have to include somethings to keep it right, but the idea is to be able to put them after glass as well. The idea is that the electronics design would be free, or very cheap, so that people can build this themselves, the casing shouldn't be to expensive but that can differ on taste, most parts or thing likes windmills would be the DIY type or possibly ones you can buy as well, and most parts would have to be, off the shelf. I'll try to add a basic drawing, and some sketches, to give you a better idea. I'm not that good at that, i'd admit.

Topic by Floris Vermeir    |  last reply


Scottish Island Stays off Grid - replaces diesels with 95% Green resources.

The Scottish island of Eigg (pronounced "Egg") has never had mains electricity, and has had to rely in expensive diesel generators for the power they do use.Devices that require 24/7 supplies, such as fridges, have been an unknown luxury.Today, though, that all changes:A renewable energy supply giving the Isle of Eigg power 24-hours-a-day has come online for the first time.The £1.6m system for the island in the Small Isles between Skye and the Ardnamurchan peninsula uses a mix of hydro, wind and solar power.It has been designed to generate more than 95% of Eigg's annual energy demand and is backed up by a battery storage system and two diesel generators.Residents have previously relied on diesel generators and hydro schemes.The dream of green power has taken 10 years to realise. A total of 45 households, 20 businesses and six community buildings on the island are linked together by six miles of buried cable that forms a high voltage network.The whole project was organised by the community themselves - at the switch-on ceremony (in the local tea shop), the island's children gathered round a candle-lit map of the island and blew the candles out as the power came on.Before the switch-on:homes were powered by diesel, wind or hydro-generatorselectricity was unreliable and restricted to certain hourssome residents went without washing machines and vacuum cleanersthe noise from the generators could be heard for milesDiesel was delivered by boat but services sometimes cancelledBBC News storyBBC Magazine article, with comments.

Topic by Kiteman    |  last reply


What material retains heat the best? Answered

I thought of something I could make for an Instructable. To keep the idea until I publish, I'll exclude the actual idea. I need a material for this project that will retain heat from a microwave for ≥20 to ≥30 minutes. It will be about 8x8x1 inches. What can I use for this? Here are some things I found to be helpful: http://en.wikipedia.org/wiki/Heat_capacity http://www.extremetech.com/extreme/130523-zeolite-thermal-storage-retains-heat-indefinitely-absorbs-four-times-more-heat-than-water http://www.fraunhofer.de/en/press/research-news/2012/june/compact-and-flexible-thermal-storage.html http://www.igb.fraunhofer.de/en/press-media/press-releases/2014/sorption-energy-storage.html

Question by knexpert1700    |  last reply


Make supercapacitors from graphite in a DVD burner

The outline is that you can deposit graphite oxide (a cheap bulk material) onto a film of PET (the plastic used in Coke bottles), hit it with a commodity infra-red laser (such as the one in a $30 LightScribe DVD burner) and end up with a form of activated carbon material that can be used as the electrode in an electrolytic capacitor.  Add some aluminium foil, separator membrane and electrolyte and you've got cheap, robust energy storage.  The headline numbers are a few hundred milliFarads per cubic centimetre at a few volts, which works out to 1.36kWh per cubic metre of stacked capacitors.  It's still about 50 times less energy per volume than lead acid batteries, but you could store as much energy as your house will need overnight in the size of a garden shed or a set of bunk beds.  They charge/discharge in seconds and retain >95% capacity at 10,000 cycles so seem suitable for storage to even out intermittent energy generation from, for example, solar or wind power. I'm really thinking about cost here- unless I'm missing something fundamental it doesn't seem like producing these on a high volume roll-to-roll process would be excessively difficult, and the cycle life means the replacement time would be many years even in heavy usage.  Could you get sufficient kWh per dollar to make these a viable storage mechanism for home-scale renewables? There's a more informative article here.

Topic by PKM    |  last reply


Low pressure pneumatic grid (1 to 4 psi) to use small wind, small hydro and small solar power?

I have used low pressure air and a simple "airlift pump"  to cycle water around a "pallet  Garden" since August.  This meant that very little water was being used but the plants were growing really well.   the air comes from an aquarium bubble pump and it is about 1 psi.  The pallet garden is almost 20 ft from the little bubble pump.   Recently I decided to do something similar in my greenhouse, but it is 120 ft from the little pump and there is no electrical socket close.  So reluctantly I bought another 120 ft of 1/4 inch tubing to send the air to the greenhouse.  I didn't expect it to work at that distance.  But it is working great. Why not use air instead of electricity to move the energy from "toy" windmills in gardens? Or from low head small water power?  I bet anyone could make a compressor to make 1 PSI.  It is orders of magnitude easier than making a direct water pump or converting the energy to electrical and then back again in a pump.  An airlift pump is just a vertical tube in the water.    How simple is that!   and it is darn cheap too.  You can use this for pumping water (Highest I ever got was 18 ft with 1 psi) or just bubbling air into a fishpond or to actually move the water in small water features.   Or of course in the pallet garden or in aquaponics.  And even thought this energy is useful at that scale it can never ever be made worthwhile to share it electrically.  But maybe your grid could extend to your neighbours garden too?  You could have an interconnector if you or they have a bit of excess pneumatic power!

Topic by gaiatechnician    |  last reply


Compressed Air Battery

A simple example of how a compressed air battery works. This one, of course, is not very efficient. https://www.instructables.com/id/Compressed-Air-Battery/

Topic by bubal    |  last reply


solar engine storing capacity problem pls suggest a suitable ckt or method to store energy for max time atleast 1 min

Hi myself abhishek frm gwalior making a solar engine using a 4700uf cap to store energy but it is not helpful to drive a motor when we remove the power frm it . the ckt is nt giving any storage we also tried 10000uf capacitor pls suggest any appropriate modification

Question by bestads27  


What's the best way to store pedal & solar power into a battery bank?

I'm looking to power some blenders & other small devices with a battery bank & I want to store power in these batteries from pedaling bicycles & possibly solar power. Just need a little help on all of the essentials and how much power I will be able to garner through a system like this. Thanks!

Question by nicksisson    |  last reply


Solar Power Towers Efficiently Using Brayton Cycle

I want to point out a solar to electric generation concept that has yet to be seen anywhere, even though it originated back during the Carter Administration's ERDA programs of the late 70's. I’m talking about solar power towers that convert solar energy into electricity at the hundreds of mega-watt level. While power towers do exist today, and the world currently does have a handful of them as shown in Fig-1, none use the Brayton Cycle nor can they boast an energy conversion efficiency at the mid to upper thirty percent level.  A group of engineers got together at a think tank organization called Sanders Associates in Nashua, N.H., several decades ago, and designed a unique Brayton Cycle, 100 MW solar Power Tower concept for generating electricity. This was accomplished under ERDA (Energy Research Development Administration) who gave us a phase-2 follow-up contract that took our phase-1 design and built a working scale model at the 10 KW level. This model was tested at the Georgia Tech Solar Research Facility and "registered" ~37% electric solar conversion efficiency. The system used ambient air as its working fluid, and was to be located in open-spaced desert regions. Phase-2 was lost to competition using a closed-loop liquid sodium system that boiled water into superheated steam at 900F to run a turbine that generated ~21% overall electric conversion efficiency.  Apparently, at that time ERDA would rather haul water out to the desert than use ambient air to generate electricity? The politics of their decision is beyond reason and clashes with improving the world’s development of green technology energy.  ERDA shut out our better technological performer and safely locked it away for another day! ERDA's official reason for turning us down: "this technology uses excessively high temperatures (2500F versus 900F) that are dangerous to workman maintaining the equipment". But that was back in the 70’s, maybe we’ve learned to deal with high-temp heat by now?   Solar Energy Concept Using Low Pressure Storage Our solar power tower would collect the sun’s energy by locating its ceramic heat exchanger on top of a tall tower as shown in Fig-1. The tower was located in the center of a field of active sun-searching mirrors (heliostats, Figure-2). These mirrors reflected sunlight onto our ceramic honeycomb heat exchanger, producing a concentrated flux intensity level that heated it to around 2500F. At the same time, low pressure fans generating only a few psi pressure would suck the ambient air through the honeycomb, heating it to just under the 2500F and then passing it through energy storage silos which stored the heat down to ~150F. We purposely designed the energy storage charging phase of our hot air system to work at only a few psi above ambient as a safety feature. The sun effectively acts as the combustor of our jet engine or Brayton cycle engine. Once the sun heats the air, it passes through heat exchangers consisting of a labyrinth of underground silos that are temperature segregated. These silos receive our 2300F airflow and cool it down to about 150F, transferring this heat into solid salt containers which turn to liquid once they have absorbed sufficient heat. Figure-3 is a schematic of this underground energy storage facility and shows the airflow being heated by a fully charged set of silos containing liquid salt-bricks. This airflow direction is reversed when we charge the silo’s salt-bricks. The bricks are kept in specially insulated, high pressure silos (located underground for added insulation) that store the heat energy at one atmosphere for later use. These underground silos act as our energy storage batteries, and when needed would discharge their heat energy accordingly into the moving airflow. This energy storage concept permitted the generation of electricity at night and during overcast days. Two sets of storage systems are required for continuous operation. One would be charging at low pressure while the other is discharging at high pressure through the Brayton engine to generate electricity.   Electric Energy Generation at High Pressure Electricity would be created by turning an electric generator at high speed. The generator was turned by running a jet engine connected to it.  The engine’s combustor for heating the air is effectively the sun, hence the name Brayton cycle for generating our solar electricity (Figure-4). The heat from the molten salt containers would increase the energy of the high pressure air coming from the compressor, and would then force it through a typical turbine that turns this energy into high rotational speed to run the generator and make electricity. Our solar jet engine sucks in ambient air using its compressor, as all jet engines do, and blows it through a series of silos at high pressure whose stacked bricks are held at different temperature levels. We start our airflow through a silo held as low as 150F and work our way up to ~2300F as we pass through our last, hottest silo which acts to complete the effective solar combustion process. This air preheating technique dramatically improves our energy turnover capability and allowed us to convert solar energy into electricity at near 37% efficiency. During our electric energy generation phase, the silos of our Brayton system requires operating at many atmospheres of pressure just as in any jet engine combustor using petroleum-based JP-fuel.      

Topic by RT-101    |  last reply


efficiency (not efficacy) of CPUs/computers? is all the power input technically converted into heat? Answered

It has recently been fairly hot where I live, especially in my room, where computer hardware seems to be increasing the temperature by a good 5-10*F over other rooms. This got me thinking, and was wondering if any computer engineers/physicists may know the answer to this one. If I am running a power-hungry intel CPU, coupled with RAM and maybe SSD storage (I wish!) is all the power fed into my system being converted into heat? In other words, if my rig consumes a good 250W-400W, and there are no transducer devices drawing power (LEDs or lights, speakers/microphones, monitors, motors, heaters, phone chargers, etc,) and all the energy is used for data collecting, and calculating, then is *ALL* the energy converted to 250W-400W of thermal energy (heat)? or do the data operations themselves in fact require energy and maybe entropy or something plays a role? where it would seem that 400W of input yields an apparent 399.981W of energy output + data.

Question by -max-    |  last reply


Paper Batteries

Has anyone read anything about the up and coming Paper (thin) batteries ? Paper Batteries: A paper battery is a flexible, ultra-thin energy storage and production device formed by combining carbon nanotubes with a conventional sheet of cellulose-based paper.A paper battery acts as both a high-energy battery and supercapacitor, combining two components that are separate in traditional electronics. This combination allows the battery to provide both long-term, steady power production and bursts of energy. Non-toxic, flexible paper batteries have the potential to power the next generation of electronics, medical devices and hybrid vehicles, allowing for radical new designs and medical technologies.What do you think? Will it replace these monsters one day?

Topic by Goodhart    |  last reply


How can I construct a piezoelectric generator using cheap materials??

Hello! I am asking this because I need help in making my research project for my fourth year in high school. The concept of my research is to harvest energy from people stepping on something similar to stairs. after harvesting the energy, I plan on storing it in a pair of AA NiMH batteries for future storage, but I am still not sure on how I will go about this. As a high school student, I don't have any advance knowledge on making generators like you brilliant people do.  Please help me. Thank you!

Question by maxene    |  last reply


Why should perpetual motion be impossible?

Our laws of physics are quite clear when it comes to the impossible.You can not produce more energy within a system than what actually goes into it.And since friction will always be a thing in our real world perpetual motion is simply impossible.With this or quite similar reactions all good scientists end the conversation.We know it is not possible, so why bother...If all that is stopping are laws of physics, then it is time to redefine "perpetual motion".Another term for it would be "free energy" as we would have to draw energy from nothing to keep it moving.Solar cells provide free energy the same way as wind- or hydro generators, we even use waves on the ocean to produce electricity...Perpetual motion seems to be defined by mechanical things and motion only.And free energy seems to be defined as bogus only while ignoring the realities.We simply can't use the same terms for everything if they are in fact totally different things....A motor running off a solar cell would be a perpetual motor if you widen the energy term a bit here.The impossible energy to run the motor comes out of nowhere - our solar cell generates electricity from sunlight.And a simple water wheel in a stream will power a mill for as long as water runs down the stream....Humanity and science say this is not free energy as we take energy from other system to make it move.And of course it is a dead simplification anyways.You get the picture though.So far humanity has only managed to tap into a very few forms of energy out there in any direct form.Solar cells come to mind first of course.In a way they utilise radiation to transform it into DC electricity.Then we have all sorts of mechanical energy transfer, from generators over windmills to the modern recovering brakes in electric vehicles.Last but not least we have heat, steam engines, nuclear reactors and so on.The laws of physics however know a few more forms of energy....We seek out new ways to "generate" more electricity than ever before, like fusion reactors.What we don't seek is understanding what we always had already.All we do it to try to "generate" electricity.It is what powers our world but it is only a tiny fraction of what is possible.We burn fuel in a comustion chamber to make piston go up and down.Only to transfer this motion into a rotary one to finally drive our wheels.Most of the energy available in the fuel is wasted this way.Making it slightly more efficient took us over 100 years....Thinking about using the fuel more directly does not even come to our minds.So why bother to consider any other possible form of energy to drive our world.We are stuck in definitions no one really understands because most of the used terms have more than one use and meaning.We fail to open our minds to other possibilities just because "that's how it is and always will be".Flying to the moon?? Impossible!We did it anyway....Using batteries to provide electricity to entire towns? What a joke!In South Australia they do it anyway and with great success as well.Powering entire cities just from wind and solar energy? Are you joking?Well, companies invest an awful lot of money here and they wouldn't do so if it would not make massive profits...So why again should perpetual motion be any different?At some stage it was hillarious to even think our world would spin around the sun.....

Topic by Downunder35m    |  last reply


Tell me more about nuclear power as source of electricity.

Hi !Fishes can't see the water they are in ! That's why I need your personal and external opinions and view.The first source of electricity in my country (France) is nuclear.In a previous forum, I've noticed that a lot of Citizen of USA consider Nuclear energy is too much polluting and too much expensive (democrats candidates for US election reject the idea of more nuclear plants), and that it's not seen as a serious solution to reduce pollution and CO2 emission, etc ... In few words : you seems to dislike it. So, I would like to know why exactly, and that you tell me more about what you think about it.Here it's quite different. Nuclear energy is seen as a mean to be energetically independent. It's a mean to pollute less. And it's almost a local speciality, like are crepes, baguettes and croissants.The main producer is EDF (which stands for Electricite De France (electricity of France)). Until 1999, EDF had the monopoly (and that was better and safer IMHO). Since then, because of EU regulation, we've been forced to open the market ...Here are some data :EDF is one of the world's largest producers of electricity. In 2003, it produced 22% of the European Union's electricity, primarily from nuclear power:nuclear: 74.5%hydro-electric: 16.2%thermal: 9.2%wind power and other renewable sources: 0.1%Its 58 active nuclear reactors (in 2004) are spread out over 20 sites (nuclear power plants). They comprise 34 reactors of 900MW, 20 reactors of 1300 MW, and 4 reactors of 1450MW, all PWRs.---In 2006 :- nuclear : 85.7%- hydro-electric : 5.0%- thermal : 8.1% ( coal : 3.3%, gas : 3.2%, petrol : 1.6% )- others renewable : 0.9% (wind, sun and co)- others : 0.3%---

Topic by chooseausername    |  last reply


Options to improve cooling and reduce consumption for portable coolers

I recently had to start learning how to service airconditioners on the fast and that learning got me thinking about my portable coolers.... Some of us like to go camping or on longer fishing trips, so there might be one of those 3-way fridges in use or a better cmpressor model. The one thing they all have in common is that they can only cool down to a difference in ambient temperatures. No matter which way we turn it the cooling produces heat and that needs to get away somehow. The other big thing is the cooling cycling - or the lack of it on a warm day. After some reading and thinking I came up with some ideas that might be applicable to your existing cooler if you are willing to mess around a bit. Let's start with the produced heat, shall we? Down here in Australia most people either have the fridge in their4WD or camper. In a car or small camper trailer there is often the problem of airflow, so the cooler might be doing overtime for no other reason than a lack of airflow. If you check online sites like Amozon and Ebay you quickly find fan systems meant to be installed inside the cooler to get lower temperatures and a quicker cooling of fresh goods. The thing is that the box is quite well insulated and the benefit of the airflow goes only as far as it can reach. And even if the box is quite empty and you would have a benefit of the cold air moving around it won't change the fact that "improved" cooling always comes with more heat in this case. But if we use one of these fan systems to actually improve the airflow on the hot side we not only get better cooling but also a reduce power consumption - something worth considering if you have no backup power generator.... This of course brings us to placement. As I have done the mistake myself you might be tempted to put a 3way cooler onto your seat. Opening it with the back free means the lid always gets stuck on the seat, do it the other way around and you block the airflow. If you do put it on the seat then make sure two things match: 1. The thing is secured properly. 2. The airflow from your aircon is able to reach the hot side of the cooler. Even permanent installations in a camper benefit from a good airflow. Often the fridge or freezer is built into some sort of bench and the airflow behind might be very limited. A simple solution here is to add a vent on top of the bench to allow the hot air to escape. A better one is to use a fan that is powered together with the heating element or compressor and drives the hot air to the outside. How to improve the cold side of the box or fridge? Well, to be honest there is not much that can be done unless you are prepared for some serious work. Depending on compartment size, contents and how full it is a little fan can help to keep the temperatures even but it won't help to get it cooler or reduce the cycling periods for the cooling. The only really working way that I found is to use a "battery" for the storage of the cold. The cooling works by checking the inside temp of the box and if above the set temp the cooling won't stop. This is all well and good while we have a constant supply of power but once we are on batteries it would be great to keep the active time to a minimum. A working solution is to build a container that fits around the cooling element. Smaller types often use an aluminium heatsink, bigger types might come with a compressor and an evaporator. In either case proper sealing is important! Most good models are fully waterproof, meaning even if you would fill them with water they would not leak in other areas than the door. But double check and if in doubt use a bit of silicone to make sure. Ok, but how do we "store" the cold coming from the device? Cold packs ;) These things contain a ready to use mix that holds cold temperatures quite well. Another really good alternative is alcohol or radiator coolant, although the last has limited capabilites in terms of holding capaity for the cold as it is desinged to exchange heat fast rather than to keep it. With a suitable sized and sealed box around the active cooling element we will need longer to actually see any cooling happen (with a warm "battery") but that can be compensated for by good planning or a frozen water bottle. If the cooling element is covered with a box of cooling gel then it has to cool this first before anything happens inside the box. But once it does the pack is already far below the normal temp it would have during normal operation. Remember the inside of the cold pack cools down first before the outside will get cold ;) So once the set temperature is reached the device will shut off. But since the cold pack is far below the set temp it will continue to cool our box until the core is warmer than the set temp. Quick thinkers will now say the benefit is lost as the time required to cool the "battery" down again is much longer than the normal cycle time - and they would be correct. But as we get much colder temps inside the gel box the overall running will still be less compared to normal operation. And since from the second cycle on the gel is only warming up to operating temp of the box it will be much faster than with a warm box. Another benefit might be the ease of cleaning and ice removal. Some peltier driven coolers have big cooling fins or a quite bad design for the heatsink allowing mould to grow where you can't remove it easy. If the box is made from stainless steel and flush with the back wall of the box we won't have that problem anymore. Ok, but how much is good or too much for the size and gel content? You got me there as it is bit tricky. You don't want to loose much usable space for starters and you don't want to wait hours for the gel to cool down if the box was not used. IMHO the size should fit the cooling element with about 20% to spare all around. If stainless steel is not an option than aluminium is the next best choice. Thin sheets can either be be cold formed with a hammer or "brazed" with a good torch and the right rods. Ok, before that route is there anything I should consider or do first? Depends ;) 3-way systems usually use a flame or heating elements to heat an ammoia solution. After years of neglect corrosion can form and reduce the amount of heat transfered into the system and reducing the efficiency this way. It might help to take the heating elements out once a year or so to clean them and the contact areas from any corrosion or dirt build up. With a fixed shedule for this you won't have the problem of never noticing a badly corroded heating element either - and this is the main failure on these systems.... Modifying your camper or making a few mods to your 4WD drawer system is not for the faint of heart and should be done with consideration. The last thing you want to do is rush things to find out it was not necessary. Before cutting holes check if you can't find the room for the fan in a different spot and use ducts to control the airflow - sometimes it is easier to blow air in than to get air out ;) When it comes to creating vents or connections for air to the outside always make sure it is waterproof and insect safe! If you can let the outlet go downwards so water won't run in, for 4WD trailers consider a flap to prevent water from going during a river crossing. Flyscreens will not only prevent insects from coming in but on the inside also prevent dust to go eerywhere - allow to the removal and cleaning! The salts used in these cold packs can be corrosive, so you have to make sure there are no leaks and that there is no steel to come into contact with gel - this includes screw ends hidden in through-holes. If in doubt use a coat of paint but keep it as thin as possible. Even on peltier systems it might be impossible to remove the heatsink without massive surgery on the internals. So before you take it all apart to gain access check if it is far easier to seal around the box opening and possible screw connections using silicone. The cooling battery can be screwed on and sealed with silicone as well as an easy escape route. Although for this to work you need to check if the material of the box allows for a proper bond with the silicone! Some materials just won't allow anything to stick at all, even after sanding them. So do a test first in an area where you would be able to cut the silicone away without causing damage. If you can rip or peel it off the surface you should not try to use a cooling battery screwed to the wall, only use a box that is fully sealed with the cooling element and has a seperate back - one complete unit around the cooling element. I have a 3-way system with a freezer compartment that does the cooling for the fridge too - what can I do? These units either provide good freezing with the fridge temps too low or good fridge cooling with no freezing capabilites - depending on the thermostat used. Our problem is that is next to impossible to add a cooling battery of the normal kind to these systems. The L-shaped freezer box can really only be added with a L-shaped cooling battery from underneath. Only if you don't need any freezing at all you could add a cooling battery to fit into the freezer box shape. In either case the benefit is somehow limited by the way the thermostat is used. If there is no temp control for freezing it should be fine. Warnings... Only peltier driven coolers are free from refrigerants. Every 3-way or compressor system uses refrigerant as evident by more or less piping and heating elements. Never attempt to screw anything into a cooling element containing refrigerant! Even if you think between the channels all will be fine it won't be! The material is just pressed to form the channels and any damage caould mean refrigerant leaking out! Use silicone instead and make sure all surfaces are properly cleaned before applying it, also wait until the silicone is really fully cured before putting any stress on it. As said, these cooling gels can be corrosive, especially if DC voltage is involved. Make sure that everything that is not aluminum or plastic is properly sealed before allowing ongoing contact with cooling gels. Do not attempt any of this if you have to ask yourself what tools you might need or how make a suitable container for the gel. If in doubt check Google on how to work with aluminium or stainless steel if there are not enough Instructables for it. The gel will expand a little bit if it freezes, this no problem in a metal container if you allow for a bit of flex or on the side added strength  - whatever suits you better. Another option is to get a few different cold packs (by the active ingredient) and to do a check in a little container. Freeze it and note whe level cold and warm. Little to no difference means nothing to worry in terms of expansion during freezing.

Topic by Downunder35m  


can v store both diferent freqncies of dc frm solar and wind in a same storag batery and can we use sme invrtr for both?

I and my friends are doing a project on hybrid energy systems solar and wind combination my doubt is that can we combine both solar and wind power which is dc and of different  frequencies is there any equipment to convert them and store in same battery .do we have to keep a single inverter or double inverter so that we can reduce our project cost and make our project at cheaper rates at 350$. please help.

Question by shane.sandilya    |  last reply


I was given a 42uF 12KV oil capacitor. Any suggestions for having some high tech fun with it? Answered

It's rated for oscillatory currents, pretty old, but it is in good cond. electrically. I can easily and safely charge and discharge it. The thing is, it was free, and I suppose I couldn't turn it down. Now what? The highest voltage I would possibly need a filter cap for is 4500 for an amplifier, so that's out. The "oscillatory currents" rating makes me think it was for energy storage and high frequencies. It is likely from LANL surplus. Can crusher? disc launcher? I'm mainly interested in suggestions for projects that will focus on a fast discharge and high peak power levels, and do not require a lot of additional items, but I am open to any decent ideas.

Question by Opcom    |  last reply


Maintaining a stable voltage on a wind turbine?

Every couple weeks a new instructable comes up on some green energy thing or another, but one I am really interested in is wind.  The problem I see is that with wind ranges from 5 - 25 mph, the voltage change is extremely problematic.  When I see people putting permanent magnets on alternators for use with wind, it seems ridiculous.  Even if you are using an inefficient battery-storage off-grid system, you still need to maintain 12-15 volts to charge your battery, and an alternator is made to do that by varying the magnetic power.  Now I understand the extremes of a alternator's voltage regulator are likely fairly narrow, but still quite useful in generating wind energy.  What I am looking at is 3-5kw of grid-tied power.  This is great and all, and possible in for me, but I don't see how I could maintain a stable enough input for it to work.  Most inverters are for solar power and aren't grid tied. The next most common are grid tied solar which take 12v DC and scale it to 115 ac across three phases.  Finding a grid-tie 5kw 3 phase in and out ac grid tie inverter is extremely hard, but not impossible.  The only thing that is impossible is finding one that can handle highly unstable voltages.  So the options I am left with are using a variable transformer to bring the wind power down to 12v and then rectifying it, then pumping it through an inverter which leaves me with 70 - 80 % of the original power.  My other option is to, like a car alternator vary the rotor voltage to maintain the desired end voltage.  The one problem I see with this is that there is a large amount of potential energy not tapped.  For example lets use 1 as the relative output as well as the input to generate a magnetic field.  If the speed is 1 then both in and out are 1.  If the speed is 2 then the in will be .5 now the out should stay at 1.  But if the in had remained at 1, then the out would be 2 so essentially you are losing half of your potential energy.  This isn't a problem in cars because they aren't tapping the maximum power possible. All the time, they don't need it.  This is a problem with wind turbines, so is there a way around this?  What wold you recommend to do for grid-tied wind power.

Question by jj.inc    |  last reply


Is my understanding of capacitors correct? Answered

I am currently working on a "Tutorial Tuesdays" video for my YT channel about capacitors covering some of the basic theory, real-world ratings and considerations, and maybe some cool demonstrations with how to use them and stuff. I just want to make sure that I do understand them correctly,so hopefully you smarter people out there can tell me if I am wrong in any way. 1) A capacitor stores energy in a electric field between two electrically insulated conductive plates, the strength of which will depend on the proximity and surface area of the plates, the dielectric constant. 2) Can I compare "electric charge" to mass; "voltage" to density; and "capacitance" to volume as an analogy? (yes, I know I am ignoring dielectric constants and strengths.) 3) If I look at the peak to peak AC current through a capacitor, and the peak to peak AC voltage, can compare the ratio of the two figures to figure out capacitive reactance? (example: If I have one volt peak to peak AC applied across a capacitor, and I see 10mA of current peak to peak, does that mean the inductive reactance is 100 ohms?) 4) Are the most important things to keep in mind with capacitors in general are "working voltage" (the maximum voltage a cap can withstand), "capacitance" (how much charge a capacitor can store for some given voltage)  "ESR" Equivalent Series Resistance, which is how 'good' the capacitor is, and "temperature" (which can potentially adversely affect the performance and ratings of a capacitor)? 5)Uses for capacitors include Energy storage, analog filters, DC removal, voltage transient suppression, voltage smoothing, timing/counting AC coupling, data storage, phase shifting, motor starting, etc. 6) The ---| |---- symbol represents a generic non-polarized capacitor      The ---| (---- or --[] []-- (with one box colored in) symbol represents polarized capacitors    The ---|/|---- symbol (with a slash in the middle being a slanted arrow) represents variably capacitors 7) Should I try to learn how to work with complex impedance (capacitors, resistors, and inductors in all sorts of weird configurations) Also, can I treat reactance in general as a resistance when looking at capacitors in series or parallel with resistive loads and stuff?

Question by -max-    |  last reply


The Eco Powerplant

  Creating a Permanent IcePack in the Eastern Sierra A permanent Ice pack in a north south valley of the Carson Basin could insure constancy of water supply to Fallon area farmers and ranchers. Creating a permanent icepack in Northern Nevada is technologically and economically feasible, given the right location . This project will be solar powered, and serve as a peaking unit during times of high electrical demand. This technology will produce energy from solar by PV Panels mounted on a giant spanning grid over a north south valley in the eastern Sierra. A properly excavated mine could also serve as a location. Proximity to gas distribution and an electrical sub line are also important . This facilities' economic importance as a producer of LNG from surplus stock cannot be overstated. The upper part of the oval consists of a space grid spanning the valley or excavation. It is covered with steerable PV panels. The PV panels may be inserted into the grid or used to create liquid air , which in turn can be used to produce LNG. The thermal energy storage as liquid air would be contained underground in the mountainside itself.In Northern Nevada, these mountains are usually solid rock formations imbedded in sandy detritus, an excellent insulating material. Vast amounts of wind power are also available during spring and summer.   During summer peak demand, liquid air could be re expanded to run generators.   And most importantly , this plant will produce as a by product of its operation large amounts of water in the desert by freezing the ground on which it operates. Wet air passing over an expanse of frozen mountain rock will condense, and either form ice or rain. The production and maintenance of a liquid air production and re-expansion facility will also produce large amounts of water during times of high humidity.   Suitable locations in the Eastern Sierra would by necessity by close to either the Truckee or Carson River Basin.    

Topic by Mud Stuffin  


Idea for a non-ideal Carnot cycle based engine.

Initial Stirling engine conceptFor some time I was contemplating an idea for a Stirling engine that would work quite differently than the other designs that I came across. Whole internal volume of an engine may be viewed as a closed-loop pipe, trombone-like slide mechanism allows this pipe to change its length. Electrical fan replaces displacer and pumps working fluid throughout the engine constantly and in one direction. Some portion of the pipe is replaced with branching structure that consist of two heat exchangers (hot and cold) and regenerator. On both ends of this structure special valves are located that connect one of the structure’s parts to the main pipe, so that whole engine forms one closed-loop. While this happens, both of the unused parts are completely bypassed.This design should have many advantages. Working gas is in constant motion and little energy is wasted on accelerating it. Gas may pass many times through heat exchangers, allowing for much better approximation of isothermal processes. Disconnecting unused heat exchangers from the rest of the engine should minimize volume of dead spaces.There are some drawbacks to. Slide mechanism allows only very small changes of total volume (compression ratio is low), and that limits engine’s ability to operate with higher temperature differences. Piston, which is part of the slide mechanism, and especially valves, are heavy and this makes them unsuited for high speed operation, making the whole engine bulky. I also except that an area of all surfaces that are sliding against each other and produce friction would be higher than in traditional Stirlings.Problems with Stirling cycleIdeal Stirling cycle (Fig. 4) consist of two isothermal processes (constant temperature) during which work is performed, and two isochoric processes (constant volume, no work performed). Isochoric processes function is only to change temperature of the working gas, and this takes a lot of energy to do so (especially if gas with high heat capacity is used). Regular Stirling engines try to minimize this inefficiency with regenerator. But when I tried to analyze this process mathematically, I noticed that even regenerator with very high heat capacity cannot store more than half the energy needed to perform next isochoric process (see lower left part of the spreadsheets for more details).Fig. 5 represents heat pump (or refrigerator) working in a modified Stirling cycle. Isochoric processes represent transfers of heat to and from the regenerator. Rest of the temperature change is performed by polytropic processes, during which heat flows to or from the heat exchangers and also work is performed. I chose to represent heat pump, instead of a engine because engine working with this modified cycle wold require isochoric processes to be performed midstroke (or transfers of heat to regenerator would have to be performed during polytropic processes, when working gas changes its temperature also due to work being performed).Note that I am using word polytropic to indicate processes where gas changes its energy both due to heat transfers and work performed. When special cases of polytropic process are mentioned (isothermal, adiabatic, isochoric) I use their specific names.Solving those problems with Carnot cycleLegendary Carnot cycle consist of two isothermal processes (just like Stirling cycle), but changes of temperature are accomplished by the adiabatic processes (no heat transfers with the surroundings), instead of isochoric ones. This has huge advantage, because when energy is added to the working gas during adiabatic compression, all of it can be later recovered during adiabatic expansion.Design I previously mentioned can easily be adapted to work as a Carnot engine. Only change that is necessary, is replacement of regenerator with the empty pipe (ADIABATIC PIPE in Fig. 2). When valves connect this empty pipe to the rest of the engine, there is no heat transfer between working fluid and thermal reservoirs. Any changes of engine volume modify temperature and pressure in a approximately adiabatic fashion. To model what happens with the engine I used slightly modified Carnot cycle (Fig.3). Just before adiabatic process end, short polytropic process begins. It is done so that loses associated with valves connecting both adiabatic pipe and heat exchanger to the main part of the engine for a short period of time can be better simulated. Heat pump working in this cycle is shown in Fig. 6.Design detailsEngine uses special valves, which external shape resemble truncated cone. Smaller base of this cone faces main part of the engine, larger one heat exchangers. Inside there is a pipe, with one opening right in the center of smaller base. The other opening is located off-center on the larger base, so it can connect to the one of the heat exchangers or adiabatic pipe (which are situated just like chambers of a revolver’s cylinder in respect to each other). As this engine engine will most likely operate under low RPMs, flywheel will have to be connected through a transmission with very high gear ratio. The flywheel will have to be quite bulky as well. This poses another challenge, as the pressure inside engine’s tubing will be higher than atmospheric, and at least space around the other side of the “piston” will have to be pressurized as well. If only the immediate surroundings will be pressurized, and gears, flywheel, electric motor/generator will be outside of the container, then very inefficient seal will have to be employed. If everything will be located inside the pressurized container, then fast moving parts will be working against dense gas. Pressure in this area ideally should have such a value, so that on every piston stroke energy is both added to the flywheel and extracted from it as to make energy storage requirements more manageable. This requirements may also be further reduced by employing some other energy storage form. And of course exchange of heat between main part of the engine and this pressurized section must be taken into consideration.Then, there is problem of heat exchangers. They can be either large diameter pipes with fins, or smaller diameter ones that are densely packed (this seems to be must popular configuration in Stirling engines). As heat transfer with the outside of the engine takes around half of the piston stroke, it might be a good idea to employ two pumps of heat transfer fluid per each of the two heat exhangers. One would work constantly to transfer heat from some large heat reservoir, the other would transfer heat to the working fluid only when it is necessary. Some another heat exchanger would have to be placed between those two circuits.And there is also a question of the piston. Basic trombone-like version could be replaced by the something similar to the design drawn in Fig. 7, where two parallel tubes, connected by U-shaped piston, are replaced by the coaxial pipes with volute on the outer section that allows connection another parallel pipe. Piston itself has then small tubular part attached which allows working fluid to pass from outer section to the inner section. This design has only one high pressure seal, is possibly lighter, but fan that pumps working fluid will probably need to be more powerful. Problem of sideways motion of the piston must also be analyzed, and it can be either resolved with piston skirts or the crosshead. Interesting aspect of this problem is that while most frictional forces in the engine are mostly independent of the engine speed, forces associated with this sideways motion of the piston increase with engine rotational speed.Another possible improvement would be making adiabatic pipe shorter than the heat exchangers, which would reduce volume of dead spaces.Engine parametersIn case of a engine that uses helium as a working fluid, has minimum volume of 46.7 liters, maximum volume of 70 liters, operates at temperatures of -5°C and 37°C with the speed of 15 RPM you can expect that it will produce 1138W of power at 8.13% efficiency.In the case of heat pump that operates at the same parameters you can expect that it will require 2300W of power and achieve COP 4.95You can find calculations, diagrams and the detailed descriptions inside non-ideal_carnot_engine.zip (it is unfortunate that Instructables do not support uploading .zip files and other file formats any more, and I have to use another website just to upload few spreadsheets).Possible applicationsI started thinking about this concept when considering applications of thermal energy storage. In more northern latitudes largest factor in domestic energy consumption is heating. So, at least in my opinion, any movement toward replacing fossil fuels with renewables should focus on this largest contributing factor. And this actually is quite fine because storing 1 kWh in a tank filled with water, rocks/concrete or simply in the ground is much cheaper than storing it inside lithium-ion batteries. And general idea behind this low temperature engine, was that some part of this large amount of energy stored to be later used to heat buildings, could be converted into electricity.It should also be able to work in reverse as a heat pump or refrigerator.

Topic by rarinn  


Attempting to create tiny, wearable, covert, simple button click counter for behavioral mod

Hi all, I've been searching both this forum and the internet in general and strangely have not come across what I'm looking to do even though to me it seems very simple. Here are the specifications/requirements of the device that I am trying to create: -extremely tiny form factor (ideally a ring sized device but I'll settle for a thin bracelet) -unobtrusive/inconspicuous (I guess a thin bracelet that could hide under a sleeve might be best) -battery powered/untethered (This is essential. The device would be useless if depended on a connection to a computer or wall socket) -battery life must last a full day -data logged is just a simple time/day stamp that would indicate when a button was clicked by the wearer      (wearer would manually click the button during the day when certain thoughts came up for him/her)       This requirement indicates that the micro controller chosen would need a clock built in and        some kind of storage - be able to upload the data to a computer I did my preliminary research considering these requirements and I came up with the following electronic components that might work: - teensy 3 (has real time clock and 2K EEPROM which should be plenty of memory for storing date stamps) - ulog (1MB of usable space across 3 analog channels, couldn't find anything about a built in clock) - Pro Micro - 3.3V/8MHz (not sure about built in real clock  but storage is 32K flash space) - OpenLog (wasn't clear about how much built in storage and didn't see any build in real time clock) These are the best I could find. If anyone has better suggestions please let me know? My idea is to connect a Mini Push Button Switch to one of the digital inputs on one these micro controllers/data loggers and write a simple sketch that records the time the button was pushed in a MMDDYYhhmm format (10 bytes per click). To power any of these micro controllers/data loggers I was planning to use a Coin Cell Battery - 12mm. I was going to sew the micro controllers/data loggers on one side of a thin piece of material that would serve as a bracelet and sew the battery on the other side. Although I'm not sure how to fix the battery to the cloth and how to connect it to the micro controllers/data loggers. I'm guessing I could find some kind of battery holder for the 12mm cell battery? Other Questions about my assumptions: Will I have enough storage left over on the flash space or EEPROM to store the data click after the sketch code has been loaded in? Will a watch battery provide enough energy to run this device all day? Is the Coin Cell Battery - 12mm the correct external power source for this project? I encourage any feed back, criticism, comments, help of any kind to move me along with this preparation so that I can move forward and purchase the parts I need. Thanks! Michael

Topic by mhussar    |  last reply


DIY DVR (PVR ?)

No, not the mythTV variety, but the real deal. I've been messing with uCLinux on various chip, which led to a vague daydream that I sketched out on the train today. These are my notes on a personal DVR. I say personal because its design for MY needs, and not the typical user. It also happens that no commercial DVR will meet these specs without being mired in lawsuits (see replayTV). Why an embedded solution and not MythTV? I've had mythtv boxes, they can be a lot of fun, and a lot of frustration. Mostly, I don't have room for a second computer, I don't want to use a ton of energy to record a few programs, and no matter where it ends up in my apartment, I will be able to hear it at night. MyDVR: I already watch all my TV on the computer. Either by TV tuner or Xvid. I don't need a Tivo style DVR that will play back content on a TV with a nice menu display. I need a mass storage device that records TV shows. I want Xvid. MPEG2 is huge. Its also kinda ugly. I really really like the look of the XVID codec. It takes a reasonable amount of space for a decent encode (~178 meg per ~20 minutes HDTV). I want multiple tuners...I mean, what if there are two (or five) programs to record simultaneously? Basic design: A motherboard with 32 bit CPU running uClinux (probably a chip from Freescale). These usually have USB and an ethernet MAC (but no PHY). USB 2.0 mass storage device emulation on the USB port. This way the unit can be hooked up to a PC for easy video extraction. This might also have some configuration abilities, but that would require a custom mass storage controller driver - YUCK! Ethernet with HTTP server for show scheduling. IDE interface to a big hard drive. The tuners and encoders would be on add-in cards. The add-in cards would have: 1. A tv tuner. 2. A DSP with xvid encoding. 3. Probably a small uC to control the DSP and tuner. Whats already in my knowledge domain (stuff that I already know about -or- could I really do it?): 1. I've been messing with uClinux for a while. What fun. 2. USB mass storage controller implementations are numerous. check. 3. Embedded HTTP server - check. But I have not routed a PCB using an external PHY. This looks messy. Perhaps a ENC28J60 instead? 4. I've been reading up on some XVID DSP implementations. There are also some commercial MP4 chips, but I bet they're pricey! 5. I picked up a bare PAL tuner at the surplus shop. Time to play. There are a few things that make this project easier than a Tivo clone. There is no video output. No need to do fancy display overlays synced to the incoming/decoding video stream. This is encode only - no need to load, decode, and display the XVID. I'm kinda testing the waters on this project. I'm going to get some DSPs and try to do real-time XVID compression. Also, I need to figure out the tuner card. Any suggestions within the scope of this project would be awesome! Especially if you've worked with uClinux and have a processor recommendation.

Topic by ian    |  last reply


Setting up a new apartment, what would you do?

Greetings all, I am soon to move to South Korea and will be sharing a bachelor with my wife on her ESL teaching contract.  I would like to see how many instructables we can take advantage of while there and want to get input from this totally awesome community and what they have used/would suggest to use. Our Goals: - Reduce energy use - Increase healthy environment/food/liquid intake - make best use of small area - nothing permanently altering structure of apartment. Example: The first problem we have to overcome is the problem of a single bed.  While it is easy to say 'just go out and buy a double or an air mattress'.  The problem is that we have to keep the original bed and have zero storage space.  The idea that I found which could potentially help through the use of a Loft Bed instructable which would help us 'lift' the single bed out of our way and allow use to effectively use it for any guest that may stay over as well as get a bigger bed into the apartment. I also saw a really neat instructable using Tesla CD-Turbine and thought maybe there may be some useful electricity to be gained since there is no water bill. Also any number of various LED projects for lights and such. I used this instructable for water filtering at home and will do so while in Korea. Any other ideas would be welcomed!

Topic by DragonDon    |  last reply


FREE DOWNLOAD 1915 ELECTRICITY FOR THE FARM

This is not a scan of the original book, but the original book converted to text with OCR, and strictly proof read with QC controls. Thus the charts, formulas can be copied and pasted into something else.  www.gutenberg.org/etext/27257   ELECTRICITY FOR THE FARM LIGHT, HEAT AND POWER BY INEXPENSIVE METHODS FROM THE WATER WHEEL OR FARM ENGINE BY FREDERICK IRVING ANDERSON AUTHOR OF "THE FARMER OF TO-MORROW," ETC., ETC. New York THE MACMILLAN COMPANY 1915   PREFACE This book is designed primarily to give the farmer a practical working knowledge of electricity for use a slight, heat, and power on the farm. The electric generator, the dynamo, is explained in detail; and there are chapters on electric transmission and house-wiring, by which the farm mechanic is enabled to install his own plant without the aid and expense of an expert.    With modern appliances, within the means of the average farmer, the generation of electricity, with its unique   conveniences,   becomes   automatic,   provided   some   dependable   source   of   power   is   to   be had—such as a water wheel, gasoline (or other form of internal combustion) engine, or the ordinary windmill. The water wheel is the ideal prime mover for the dynamo in isolated plants. Since water-power is running to waste on tens of   thousands of our   farms throughout   the country,   several chapters are devoted to this phase of the subject: these include descriptions and working diagrams of weirs and other simple devices for measuring the flow of streams; there are tables and formulas by which any one, with a knowledge of simple arithmetic, may determine the power to be had from falling water under given conditions; and in addition, there are diagrams showing in general the method of construction of dams, bulkheads,   races, flumes, etc.,   from materials usually to be found on a farm. The tiny unconsidered brook that waters the farm pasture frequently possesses power enough to supply the farmstead with clean,   cool,   safe   light   in place of   the dangerous,   inconvenient oil   lamp;   a   small   stream capable of developing from twenty-five to fifty horsepower will supply a farmer (at practically no expense beyond the original cost of installation) not only with light, but with power for even the heavier farm operations, as threshing; and in addition will do the washing, ironing, and cooking, and at the same time keep the house warm in the coldest weather. Less than one horsepower of energy will light the farmstead; less than five horsepower of energy will provide light and small power, and take the drudgery out of the kitchen.   For those not fortunate enough to possess water-power which can be developed, there are chapters on the use of the farm gasoline engine and windmill,   in connection with the modern storage battery, as sources of electric current.   www.gutenberg.org/etext/27257

Topic by Lateral Thinker  


How much Mercury is in Compact Fluorescent (CFL) bulbs, watch batteries, and coal-fired power plants?

In Brennn10's Compact Fluorescent Instructable there was a short discussion about the amount of mercury contained in CFL bulbs. The same topic came up in a mailing list I read, and there was some interesting analysis worth sharing.Statement:The Stranger (the Seattle weekly) has a column called "Dear Science" where the typically quite intelligent author argued that CFL bulbs weren't all that "better" for the environment because inevitable improper disposal put more mercury-n-shit into the environment. So unless you got all your power from a mercury spewing coal plant, you shouldn't use CFL's . And Seattle, getting a majority of it's power from hydro, shouldn't use CFL's.This was called into question for being selective analysis that encourages an attitude of "there's not currently a solution, so keep doing what you're doing", and elicited the following response:Just so I can bore everyone with what I think is the current level of knowledge about mercury and CFLs, here's some of the current information.NRCan did a study on how much mercury is actually in CFLs, and compares them to other typical consumer sources (e.g., watch batteries--if you throw one of them out, you've throw out five times as much mercury as in a CFL):http://oee.nrcan.gc.ca/energystar/english/consumers/questions-answers.cfm#mercuryAfter reading this, I actually worked out these numbers for myself on how CFL savings compare to mercury releases a few months ago. Of course, this is all more environmental destruction brand X vs. brand Y discussion that was being talking about.I was curious about what the numbers work out to, so I went to dig for some data; this is what I came up with.In 1999, about 1.75 trillion kWh were generated by coalEnergy Information Administration Annual Energy Review 1999, Figure 26In 1999, 47.8 tons/year of mercury emissions came out of coal-fired power plants.Source: U.S. EPA, Office of Air Quality Planning and Standards.1999 National Emissions Inventory for Hazardous Air Pollutants.http://www.epa.gov/ttn/chief/net/1999inventory.html#final3haps.This calcs out to a figure of 0.025 mg mercury per kWhAssuming 5 mg mercury per CFL, the equivalence point is about 200 kWh--a CFL would need to save 200 kWh before getting tossed in the trash. A quick calculation shows that this is about how much a CFL saves in half a year, if it were run 24-7: 75 W for an incandescent; 25 W for an equivalent CFL = 657 vs. 219 kWh/year, or 438 kWh/year difference.Of course, this assumes that the coal mercury emission rate is the same as it was in 1999; I'm not sure if measures have been taken since then to reduce mercury emissions. Also, this is assuming that 100% of the power saved by the CFL would be generated by coal-fired power plants. But even with that assumption, coal is such a large fraction of the power generation (typically about half)--it would jump from six months to a year, instead. Of course, this period gets longer assuming a realistic duty cycle, but still, those numbers all seem to pencil in below typical installed lifetimes of CFLs.Finally, there's a article from Home Energy magazine (behind a subscriber link), where somebody did a similar calculation with more current numbers, I think.http://www.homeenergy.org/article_full.php?id=457&article;_title=Understanding_CFLsHome Energy MagazineNovember/December 2007Understanding CFLsby Richard Benware"Although the use of CFLs is steadily spreading, public understanding about how to dispose of them responsibly has not kept pace."Life Cycle BenefitsIn order to disprove the myths about CFLs, let's begin at the beginning. When CFLs are created, manufacturers dose the bulb with a small amount of mercury. This mercury, when electrically stimulated, releases UV light, which subsequently reacts with a phosphor coating to create visible light. Thus mercury is an essential part of every CFL; without it, the bulbs would not produce light. The typical dose of mercury is about the size of a pen tip, and these doses have been getting smaller and smaller. One reason for this is that the laws resulting from the Restriction of Hazardous Substances (RoHS) Directive have made it illegal for CFLs in Europe to contain more than 5 milligrams (mg) of mercury.In the United States, there are no such laws limiting the amount of mercury in lightbulbs as yet, but members of the National Electrical Manufacturers Association (NEMA) have voluntarily agreed to limit the amount of mercury in the CFLs that they produce to 5 mg for bulbs of up to 25 watts and 6 mg for bulbs of 25 to 40 watts. The average CFL on store shelves today contains about 4 mg of mercury, and nearly all the CFLs in production contain less than 5 mg. The mercury used in all the CFLs produced in the United States represents 0.18% of the mercury used in all U.S. products andindustrial processes.CFLs do not release mercury as long as they are intact. In fact, they reduce net mercury emissions in the environment by conserving energy. For every kWh of electricity used by consumers, the average power plant emits over 1.5 lb of pollutants. If a 75W incandescent is replaced by an 18W CFL, the CFL will use 456 kWh less energy than the incandescent over its 8,000 hour lifetime. The Emissions and Generation Resource Integrated Database (eGRID) contains data on the emissions of the average power plant. Using eGRID's information to calculate the average emissions per kWh, we find that this single CFL has prevented the release of 2.72 lb of sulfur dioxide, 1.05 lb of nitrogen oxide, 5.67 mg of mercury, and over 700 lb of CO2.It is important to note that these are the reductions from the average U.S. power plant. The eGRID data show that, on average, nonbaseload emissions tend to be dirtier. And in addition to reducing emissions, CFLs save money for the consumer. The Energy Information Administration (EIA) gives a 2006 average residential electricity cost of $.1008/kWh. Using the example given above, and basing our calculation on this figure, we find that a consumer would save about $46 on energy over the lifetime of the CFL.When these bulbs finally do reach the end of their useful life, there are several pathways they can take. In the best-case scenario, the bulbs are recycled. Recycling rates are increasing, thanks to state regulations -- California and Minnesota have banned altogether throwing CFLs in the trash -- and improved consumer awareness. In 1999, it was estimated that only 15% of all fluorescent lightbulbs were recycled. Currently, that number has increased to around 25%, with higher levels in commercial applications. Since an average of 98.9% of the mercury is successfully recovered in the recycling process, this pathway generates minimal emissions.Even the CFLs that are discarded in the trash are unlikely to release much of their mercury. Although most of them break under current trash disposal methods, some remain unbroken, and will not release any mercury. But those that do break are not likely to release much mercury. EPA estimates that only 0.2% of the remaining mercury in a spent bulb is elemental vapor. The rest of the mercury is in the glass, the phosphor coating, and the electrodes of the bulb. Mercury absorbed in these areas is not readily released. In fact, an EPA study found that only 6.8% of the total mercury in a broken bulb will be released. Since the average bulb on the market today contains only 4 mg of mercury, it will release only about 0.27 mg, even if it breaks when it is thrown in the trash.The only disposal option that could lead to the release of any significant amount of mercury is incineration. Today, many incinerators have advanced mercury control technologies. CFLs disposed of in such incinerators would release up to 90% of their mercury, but those emissions would then be removed by these technologies. Incinerators without these technologies are not capable of removing the mercury. But even after accounting for all of the emissions that occur via all of the routes listed above, CFLs represent a mere 0.01% of total U.S. mercury emissions annually.It is important to note that even if CFLs released all of their mercury, the environment would still be better off than it would be if nobody used CFLs. This is true because the average power plant releases 5.67 mg of mercury to power each 75W incandescent bulb. In short, replacing incandescents with CFLs is a great way to save energy, reduce mercury emissions, and save money (see "Discounting CFLs").

Topic by ewilhelm    |  last reply


Very Small Scale Power Generation in Developing World

Hello Everyone, I volunteer for a non-profit which distributes solar lanterns primarily to students as well as people who are in need of the lights.  Things have been going well but a lot of people have inquired about us providing access to a higher powered version for various reasons and we've noticed that some households go back to their old ways when the lanterns don't receive enough sun during the day.  Temporarily we are solving the problem by having local entrepreneurs charge batteries for the families for a small fee but we feel that this should not be a permanent solution. It's not the price that's the issue it's that sometimes the people have to walk for a number of kilometers to get to the nearest charging station or have to cross dangerous terrain (I have personally experienced this). Over the last 3 years we have helped over 5000 families by giving them solar lights so we would like to modify all those units to have more stable energy generation. Our current version has an output of 5 watts. We are looking to buy or build a unit which produces a maximum 8wh an hour until the fuel source runs out or something that can generate in a more slower rate such as 40wh in 16 hours so we can let it run overnight and have the power stored in a battery. We are primarily a donation driven group so something with low cost and maintenance would be really great.  We highly subsidize the price to a large percentage of the households but we also provide them free for the lowest 10% of households who can't even afford the lowered price. I personally think that something which can generate electricity from hydrocarbons due to their high energy density and easy access would be ideal but I'm not an engineer so what do I know.  I'm not sure if this helps in any way but a number of years ago we transitioned a large number of houses from wood fired stoves to gas and as all the families that we help actually have access to gas I was wondering if any good technology exists where electricity can be generated by gas that can meet the low cost and maintenance criteria.  I've looked into thermoelectric generators but they are really inefficient and people will be wasting money to heat their house in a country where average temperatures are in the 30'sC I also see a future issue regarding battery degradation as we use small lead acid batteries and while thinking of a way to solve this I came up with the following idea and is one of the reasons that I'm posting on instructables. What if a pedal powered flywheel generator was built with a 200W generating capacity and 40Wh worth of 'storage'.  When you pedal you will spin up the flywheel and it will store the energy until you need the electricity again and we could also wire up the solar panel that we already use to spin up the flywheel.  So when the sun is out the panel is used and on rainy days and during the night you pedal for a couple of minutes for one hour of lights.  If the flywheel can store the energy for a number of hours then someone could pedal for a couple of minutes at a time throughout the day and not have to do it at night. This is just an idea that I came up with and if anyone has any ideas I'll be really interested in knowing about it (obviously the above solution is not ideal because they have to put some work into generation but it's the best that I can do).  I've quite recently been looking into different types of fuel cells powered by m/ethanol and others like solid oxide cells and they seem interesting (does anyone here have any experience in building these type of cells?).  This community has a lot of intelligent members who think outside the box so I'm confident that we can come up with something. This ended up being a bit longer than expected and if you've read this far, thank you. I wasn't sure about what section to post this in, square peg is the one I chose out of 5 so if this is wrong please feel free to move it to the correct section. Help and advice will be very much appreciated. Kindest Regards

Topic by ragun8    |  last reply


The K'nex Innovations Challenge (KIC) - Round 1 (UPDATES, PLEASE READ)

Seeing as a lot of interest in the challenge has been expressed, the judges and I have decided to host this round now. This round's chosen topic is: Weapons Any weapons are permitted for posting, so long as:  -They are functional - all guns must fire.  -They are your own design - this means that no modifications of other guns will be accepted.  -They are posted between the deadline times. Any posted outside these times will not be accepted. It is also not acceptable to re-post.  -They are posted on the site in the form of an Instructable, Slideshow, or Video. The more detailed your submission is, the more likely we are to understand your submission. Please use correct english and annotate where appropriate - we are judging on many criteria!  -They only use K'nex pieces, rubber bands (or other means of elastic potential energy storage) string and tape. Cut pieces are permitted, but do take into account that more cut pieces won't get you better marks. We are trying to maximise the potential of K'nex, not mutilate our pieces! Please post your entries at any time from: 12:00 Midday GMT September 1st and no later than: 12:00 Midday GMT October 1st.   (Central American Time = 6:00 AM) Entries will not be accepted if they are posted beyond the deadline, no exceptions. To submit your entry, post an Instructable, Slideshow or Video of your weapon, titled "KIC Entry: - " You must post a link to me on this forum topic, or via Private Message. Judging will commence immediately following the final deadline. The top 20 highest-scoring entries will qualify for round 2. Please use this topic for general discussion and submission - no spam please, it makes judging and entry accepting much harder. You have one month. Good luck! List of Entries: Beanieostrich Seleziona Masterdude KnexFreak360 rec0n EDIT: Thanks to a suggestion from TheDunkis and Dj Radio, I am allowing teams to work on a single project in order to share ideas and optimise the weapon.

Topic by The Jamalam    |  last reply


Throwies reimagined - Really I did tried :) :| :/

Seeing other forms of making interactive throwies, eg using microchips impresses me.However i think it is important that we try parts of the B.E.A.M philosophyhttp://en.wikipedia.org/wiki/BEAM_roboticsNamely keeping things simple, and avoiding the use of microprocessor.The component of a interactive throwie is that it has1. Power storage2. Trigger3. Circuit4. LED5. (optional) Power collection of radiant energy.I like to see more suggestion on ways we can address each issues.But to kick start the issue, can you see if my idea is feasible.essentially for my prototype not-yet throwie, I used a circuit from http://unconventional-airsoft.com/2003/11/16/momentary-fan-switch/#more-21to create a throwie that on sensing motion, doesn't flicker but turns on for a while.By ensuring that i use few and simple componants, i hope to keep cost per throwing down.Unfortunately my problem is that using a resistor to keep the capacitor from draining too fast from the base, actually decreases the voltage drop to an unacceptable level at the led.On my end it is unsolvable for the moment. Maybe you can work out how to make a cheap throwie, that can still do these functions or more.Any ideas how to solve this?Other Ideas for throwies1.Open and attach a switch to a barometer, to have a air presser passive trigger.2. A leave shaped pad with two conductors that do not touch, to act as rain sensors. (Resistance increase when leaf dries)3. Is sensitive to infrared radiation from side, so that the throwie is trigger-able by other activated throwies. (As well infrared devices)4. Has a short loop of coil to recharged capacitors, by outside induction.5. If activated rarely, uses a tiny single solar cell to charge capacitor.6. Has a hook to be easily collected for recycling. (Using a simple loop of wire on a pole [Like a dog catcher pole] )7. A single thermistors in series with led.8. A tricolour LED, and a Two light resistor. One LDR acts to sense if it is day an night, if night a low power light is activated. Only when an object strays near, and reflect light into another LDR, does the throwie get triggered at all.9. A throwie triggered by vibration.10. A throwie that responds to radio waves.

Topic by akimbo m    |  last reply


building winter greenhouse.... need ideas

Hi there,I live in Boston, MA and I am looking for some advice on Greenhouse construction for winter gardening only (and vegetables that are appropriate for that as well). I am looking to build a greenhouse that I can put up in the fall and take down in the spring for growing a winter garden. It will have to be able to be taken apart into its components and stored in a shed in summer months since my family has no need for it then. Due to the fact that it will be used in the winter, it will have to be highly insulated and have a heat sink that will be able to help maintain a constant growing temperature for the plants inside. Ideally I would like to avoid expending much energy heating the greenhouse. I am, of course, also doing this on a budget. Here is what I have come up with so far. 1. I will use triple-wall or 5 wall polycarbonate panels for the walls of the greenhouse2. I have found a few insulating products that look like they could be useful3. I am thinking of using a solar collector water heater as part of the heat sink- easy to construct on my own : https://www.instructables.com/id/Solar-Thermal-Water-Heater-For-Less-Than-Five-Doll/ that could circulate hot water into the heat sink4. I am learning about heat sinks and thinking that I want to use the simplest design and organic materials (mud, rocks, or water) to hold the heat during the day and release it at night.5. The greenhouse footprint can’t be larger than 8’ x 10’ 6. I prefer the simplest construction that meets my needs (and the easiest to put up and take down)Questions that I have:1. What are the possibilities for using compost as a source of heat?2. What about a PVC frame?3. How would I circulate hot water through the heat sink?4. What are methods to reduce daily management of the project?5. Types of hinges to use?6. What type of material should I place the greenhouse on?- it will be sited on the concrete area around our swimming pool and I don’t know what sort of insulation is necessary after that. I had the idea of wood pallets with insulation inside them but that may not be enough at all.7. Any ideas of ways to re-use materials to do this cheaply and reduce waste?8. Any suggestions on the optimal shape of the greenhouse roof/sides to increase heat retention and circulation of warmer air.9. Any suggestions of retailers that might have the materials that I am looking for.Some links that have been useful so far:http://attra.ncat.org/attra-pub/solar-gh.html#storagehttp://growerssupply.com/farm/supplies/cat1;gs1_greenhouse_building_materials;gs1_corrugated_sheets_panels.html

Topic by ocea46    |  last reply


need ideas on greenhouse

Hi there,I live in Boston, MA and I am looking for some advice on Greenhouse construction for winter gardening only (and vegetables that are appropriate for that as well). I am looking to build a greenhouse that I can put up in the fall and take down in the spring for growing a winter garden. It will have to be able to be taken apart into its components and stored in a shed in summer months since my family has no need for it then. Due to the fact that it will be used in the winter, it will have to be highly insulated and have a heat sink that will be able to help maintain a constant growing temperature for the plants inside. Ideally I would like to avoid expending much energy heating the greenhouse. I am, of course, also doing this on a budget. Here is what I have come up with so far. 1. I will use triple-wall or 5 wall polycarbonate panels for the walls of the greenhouse2. I have found a few insulating products that look like they could be useful3. I am thinking of using a solar collector water heater as part of the heat sink- easy to construct on my own : https://www.instructables.com/id/Solar-Thermal-Water-Heater-For-Less-Than-Five-Doll/ that could circulate hot water into the heat sink4. I am learning about heat sinks and thinking that I want to use the simplest design and organic materials (mud, rocks, or water) to hold the heat during the day and release it at night.5. The greenhouse footprint can’t be larger than 8’ x 10’ 6. I prefer the simplest construction that meets my needs (and the easiest to put up and take down)Questions that I have:1. What are the possibilities for using compost as a source of heat?2. What about a PVC frame?3. How would I circulate hot water through the heat sink?4. What are methods to reduce daily management of the project?5. Types of hinges to use?6. What type of material should I place the greenhouse on?- it will be sited on the concrete area around our swimming pool and I don’t know what sort of insulation is necessary after that. I had the idea of wood pallets with insulation inside them but that may not be enough at all.7. Any ideas of ways to re-use materials to do this cheaply and reduce waste?8. Any suggestions on the optimal shape of the greenhouse roof/sides to increase heat retention and circulation of warmer air.9. Any suggestions of retailers that might have the materials that I am looking for.Some links that have been useful so far:http://attra.ncat.org/attra-pub/solar-gh.html#storagehttp://growerssupply.com/farm/supplies/cat1;gs1_greenhouse_building_materials;gs1_corrugated_sheets_panels.html

Topic by ocea46    |  last reply


Acer laptop, what mother board does it use?

 I have a acer aspire 5542, And would like to know the mother broad it uses Thanks for your help Brand Acer Model Aspire 5542 Operating system Windows 7 Home Premium 64 Bit Processor / Graphics AMD Athlon II Dual-Core M300 2.00 GHz ATI Mobility Radeon HD 4200 Series Memory 4 GB Dual-Channel DDR2 SDRAM 667 MHz Hard drive SATA 500 GB HDD 5400 rpm Display / Resolution 15.6-inch HD 1366×76 resolution high brightness Acer CineCrystal TFT LCD, 16:9 aspect ratio, 8 ms response time, 60% color gamut Removable Storage 8X DVD-Super Multi double-layer drive Wireless Support Atheros AR5B93 Wireless Network Adapter 802.11 n, b, g Communications Broadcom NetLink Gigabit Ethernet, HDAUDIO Soft Fax Modem with SmartCP, Acer Video Conferencing with Integrated Acer Crystal Eye Webcamer featuring 640×480 resolution, Bluetooth 2.1 Input Devices Full-size keyboard including number pad, Synaptics touchpad with Multi-Gesture support Power 6-cell Li-ion with up to 3 hours of battery life Accessories Extra battery, external USB floppy, extra AC adapter Security software/features Acer Backup Manager1, Acer Bio-Protection1, Acer eRecovery Management, McAfee® Internet Security Suite 2009 Trial, MyWinLocker®, Nortonâ„¢ Online Backup Other Software Acer Arcadeâ„¢ Deluxe featuring Acer CinemaVisionâ„¢ and Acer ClearVisionâ„¢ technologies, Acer Crystal Eye, Acer GridVistaâ„¢, Acer Launch Manager, Adobe® Flash® Player, Adobe® Reader®, EarthLink®1, eSobiâ„¢, Google Toolbarâ„¢, Microsoft® Works with Office Home and Student 2007 Trial, NetZero®, NTI Media Makerâ„¢, Oberon GameZone, WildTangent® Memory card reader Media Card Reader supporting SD, MMC, RS-MMC, MS, MS Pro, xD Accessible memory slots 2 slots Maximum Memory Expansion Up to 4 GB Ports Headphone/speaker/line-out jack with S/PDIF support, Microphone-in jack, Line-In jack, Ethernet (RJ-45) port, Modem (RJ-11) port, DC-in jack for AC adapter Additional Ports None Audio Dolby®-optimized surround sound system with two built-in stereo speakers, Optimized 3rd Generation Dolby Home Theater® audio enhancement, featuring Dolby® Digital Live, Dolby® Pro Logic® IIx, Dolby® Headphone, Dolby® Natural Bass, Dolby® Sound Space Expander, Dolby® Audio Optimization, Dolby® High Frequency Enhancer technologies10, True 5.1-channel surround sound output High-definition audio support S/PDIF (Sony/Philips Digital Interface)11 support for digital speakers, MS-Sound compatible Built-in microphone ENERGY STAR Qualified Energy Star 5.0 Weight 6.16 lbs (2.8 kg) with battery Dimension 15.1 x 9.9 x 1.03 to 1.5 inches, 383 x 250 x 26 to 37 mm Thinness 1.03 to 15 inches, 26 to 37 mm Network Card Broadcom NetLink Gigabit Ethernet, HDAUDIO Soft Fax Modem with SmartCP PC Card Slot None Webcam Acer Crystal Eye Webcamera featuring 640×480 resolution Multimedia and Entertainment Acer Arcadeâ„¢ Deluxe featuring Acer CinemaVisionâ„¢ and Acer ClearVisionâ„¢ technologies, Acer Crystal Eye, Adobe® Flash® Player, NTI Media Makerâ„¢, Oberon GameZone, WildTangent® Warranty Limited 1-year and 90 day warranty options available depending on country, 1-year limited warranty on primary battery. Optional HP Care Pack Services extended warranty

Question by andreblue  


Distribution of Solar Heated Water and Any Other Heated or Cooled Water

I started this project about a week ago after seeing the Instructable – https://www.instructables.com/id/How-to-build-a-strikeheliostatstrike-paraboliI made mine out of cardboard and then coated the cardboard – front and back – with fiberglass resin for stiffness. I covered the inside with tinfoil to test it out and find the focal point. It worked great with the focal point at the center of the dish even with the lip of the curve. I then removed the tinfoil and replaced the tinfoil with mirrored Plexiglas. Now it works awesome. I have a 30� parabolic mirror that can ignite wood almost instantaneously at the focal point of the light.Next I constructed the heating coil to run water through. This is made from a large 1 Kg coffee can, 16’ of ¼� copper tubing with end fittings, and the glass lid of a small sauce pan (handle removed). The outside of the coffee can is painted flat black as is the copper pipe. The copper pipe is coiled to a coil 4� in diameter and 6� in length and inserted inside the can with the ends extending from the side of the can through two drilled holes. The inside of the can is not painted, but left shiny. The glass lid is then taped over the hole with aluminum metal tape covering a minimum amount of the glass – about 1/4� around the edge.The coffee can is then suspended over the mouth of the parabolic mirror by a three point 6� chimney pipe stand-off. The can’s mouth is centered at the focal point of the mirror so all of the light being reflected by the mirror must enter the coffee can. Hoses are hooked up to the copper pipe fittings and these lines go to the feed/storage tank.The problem with the conventional set up from here is that the speed the water moves at (slow) to be heated to a great degree causes such great loses through convection, this system is not really feasible. I propose a new idea – or a new twist on an old idea.I noticed that the solar heat generating station use a black water pipe inside a glass vacuum tube to generate heat from the sun for heating water. I said to myself that this is a great idea and plan on building the next heating coil in a vacuum chamber. But, I also came up with the idea that the if the water is heated in this manner, why can’t it be transferred to the storage tank in a similar manner.If the feed lines were suspended inside a larger outer line and the outer line sealed tight and vacuumed the heat transfer due to convection would be almost nil. I estimated that with a total convective area at 100% the use of plastic stand-offs (8 @1/8� thick over 12’) the convective area would be reduced to 0.6%. Unbelievable! Even if this rose to 5% it is far beyond anything in use today by the home owner. Stretches of pipe going 100s of meters would no longer be un-heard of. You could place the dish in a close by field away from the trees and house and pump the heat back without losing it to the ground.This would also work for outdoor wood furnaces if use today. An outer pipe could be added over the existing pipe work, sealed, and vacuumed – almost all heat lose would be gone. And much larger stretches of pipe could be used here also. They would no longer need one furnace for the barn and another for the house. With this system, the pipes could even be run above ground, if desired, in some cases.This could also be used to replace insulation on cooling lines also.The key to the system is minimal contact between the inside and outside lines, and the vacuum between the two lines. Remember, there is no transfer of heat through convention within a vacuum, because there is no air for the heat to transfer through.As with all the new ideas this could get costly depending on the scale of piping you are dealing with – but the savings from reduced heat lose will far out way these cost in the near future.I may get an Instructable out for the Energy efficiency contest, but will be hard pressed.

Topic by strmrnnr    |  last reply


Record Solar Powered Flight

UK-built solar-powered plane has set an unofficial world endurance record for a flight by an unmanned aircraft.The Zephyr-6, as it is known, stayed aloft for more than three days, running through the night on batteries it had recharged in sunlight.The flight was a demonstration for the US military, which is looking for new types of technology to support its troops on the ground.Craft like Zephyr might make ideal platforms for reconnaissance.They could also be used to relay battlefield communications.Chris Kelleher, from UK defence and research firm QinetiQ, said Unmanned Aerial Vehicles (UAVs) offer advantages over traditional aircraft and even satellites."The principal advantage is persistence - that you would be there all the time," he told BBC News. "A satellite goes over the same part of the Earth twice a day - and one of those is at night - so it's only really getting a snapshot of activity. Zephyr would be watching all day." The latest flight was conducted at the US Army's Yuma Proving Ground in Arizona.The Zephyr flew non-stop for 82 hours, 37 minutes.That time beats the current official world record for unmanned flight set by the US robot plane Global Hawk - of 30 hours, 24 minutes - and even Zephyr's own previous best of 54 hours achieved last year.However, the Yuma mark remains "unofficial" because QinetiQ did not involve the FAI (Federation Aeronautique Internationale), the world air sports federation, which sanctions all record attempts.The US Department of Defense funded the demonstration flight under its Joint Capability Technology Demonstration (JCTD) programme. The 30kg Zephyr was guided by remote control to an operating altitude in excess of 18km (60,000ft), and then flown on autopilot and via satellite communication.It tested a communications payload weighing approximately 2kg.At first sight, the propeller-driven Zephyr looks to be just another model aircraft, and it is even launched by hand. But this "pilotless" vehicle with its 18-metre wingspan incorporates world-leading technologies.Its structure uses ultra-lightweight carbon-fibre material; and the plane flies on solar power generated by amorphous silicon solar arrays no thicker than sheets of paper. These are glued over the aircraft's wings.To get through the night, the propellers are powered from lithium-sulphur batteries which are topped up during the day."A lot of effort has gone into power storage and light-weighting the systems," explained Mr Kelleher. "Lithium sulphur is more than double the energy density of the best alternative technology which is lithium polymer batteries. The engineers from the Farnborough-based company are now collaborating with the American aerospace giant Boeing on a defence project codenamed Vulture.This would see the biggest plane in history take to the sky, powered by the sun and capable of carrying a 450-kilo (1,000lb) payload.US commanders say the design must be able to maintain its position over a particular spot on the Earth's surface uninterrupted for five years. QinetiQ is the public company that used to be the British Government's military research department, before they privatised it.BBC articleQinetiQ's page on Zephyr

Topic by Kiteman    |  last reply